Blinding eye diseases include a number of disorders that effect vision. Age-related macular degeneration (AMD) is the leading cause of ocular dysfunction, including blindness. One form of AMD, non-exudative AMD, also known as “dry” AMD, is typically characterized by drusen accumulation within or external to the retinal pigment epithelium (RPE). Late in dry AMD, atrophy of the RPE and the overlying rod and cone photoreceptors occurs. A second form of AMD, exudative or “wet” or “neovascular” AMD, is characterized by choroidal neovascularization. Early stage disease is frequently dry AMD while later stage disease is frequently either wet (neovascular) AMD or dry (atrophic) AMD.
Drusen are whitish spots or deposits that occur within the RPE or external to it. Drusen are the defining or pathognomic feature of AMD. By contrast, the terms “pseudodrusen” or “drusenoid deposits” or “subretinal drusenoid deposits” have been used to describe discrete deposits or a yellowish curvilinear or reticular pattern that are suggested to lie anterior to the RPE, relative to the path of light entering the eye, in the sub-retinal space.
Because of differences in imaging techniques, there is controversy around the prevalence of reticular pseudodrusen (RPD), with many hypothesizing that it is under-estimated. Like AMD, RPD is associated with aging. RPD is also strongly associated with vision loss, typically due to geographic atrophy or choroidal neovascularization. Unlike classic AMD, it is however characterized by an interlacing, curvilinear or reticular pattern that can be visualized in multiple wavelengths of light including but not limited to white, blue, blue autofluorescence, red-free, near infra-red or infra-red. The defining or pathognomic feature of RPD is not drusen but rather “pseudodrusen”, “drusenoid deposits” or “subretinal drusenoid deposits” that appear as base-down domes, triangles or spike-like deposits that lie anterior to (above) the RPE in the subretinal space, when evaluating the outer retina and RPE in the transverse plane, as can occur optically using for example, optical coherence tomography (OCT) or in post-enucleation samples using for example, histology with or without immunohistochemistry. Unlike classic AMD, RPD may be associated with increased cardiovascular death. At present, without wishing to be bound by theory, RPD may be considered a distinct form of age-related macular disease rather than a subtype of AMD. RPD may also be considered to be a “diffuse-trickling” subtype of dry AMD.
There is presently a paucity of drugs for effective treatment of blinding eye diseases, such as AMD or RPD. Therefore, there remains a need for therapies that are useful for treating these diseases and other blinding eye diseases. Further, there is a need for effective diagnosis of these diseases.